military challenge coins as of mid 2007
From bottom left column:
Basic Military Training: 322d Training Squadron and Airman's Coin.
Tech school: 336th Training Squadron and 3C0X1 coin.
50th [now Space] Communications Squadron and 50th Communications [now Network Operations] Group.
Deployment coins: Squadron CC coin, 380th Expeditionary Communications Squadron, Expeditionary Mission Support Group, Air Expeditionary Wing, and the Embassy.